(1) Field of the Invention
The present invention relates to a presensitized plate from which a lithographic printing plate is to be prepared, and particularly to such plate having a silver halide light-sensitive layer which is to be exposed to argon-ion laser beam for the preparation of the printing plate, and which is high in sensitivity and can be handled under a safe light.
(2) Prior Art
There is known a process for preparing printing plates, including the step of exposure of a presensitized plate to a laser beam so as to produce an image on the plate, in which argon-ion laser beam is usually used. As a suitable presensitized plate for such process, there has been used a silver halide photographic film. However, in preparing a printing plate for lithography, a presensitized plate having a silver halide light-sensitive layer has a drawback in that it is less sensitive to a low-energy argon-ion laser beam while enhancement in the sensitivity will result in difficulty in handling the plate under a conventional safe light.